Medical appliance

ABSTRACT

The invention contemplates a non-invasive technique and apparatus for artificially stimulating the venous-return flow of blood from the foot by inducing sharply pulsed squeezing or necking-down of the vessels of the venous-pump mechanism within the foot. The sitmulation results from transient flattening of the plantar arch, in that an induced transient spread of the heel with respect to the ball of the foot stretches, and therefore necks-down involved blood vessels; stimulation also results from such a squeeze of the plantar-arch region as to concurrently squeeze the involved blood vessels. Cyclically inflatable devices, local to the foot-pump region, are disclosed for inducing either or both of the indicated actions.

RELATED CASES

This application is a continuation of a first copending application Ser.No. 763,686, filed Aug. 8, 1985, and said copending application is acontinuation-in-part of our originally filed application Ser. No.621,499, filed June 18, 1984; this application is also acontinuation-in-part of a second copending application Ser. No. 751,150,filed July 2, 1985, now abandoned, and said second copending applicationis a division of said original application Ser. No. 621,499, filed June18, 1984,.Iadd., which claimed priority from United Kingdom applicationNo. 8316959, filed June 22, 1983 and United Kingdom application 8330138,filed Nov. 11, 1983. .Iaddend.

BACKGROUND OF THE INVENTION

The invention relates to a medical appliance, and particularly to amedical appliance for applying pressure to a part of a human body forthe purpose of stimulating blood circulation.

Such medical appliances are known which comprise a double-walled sheathadapted to fit over a limb, for example an arm or a lower leg portion,to be treated, and a pump apparatus arranged to inflate and deflate thesheath cyclically thereby to apply a pumping action to the limb and thusassist venous blood-flow therein.

A particular disadvantage of such known appliances is that they cannotbe used when the limb to be treated is also to be encased in a plastercast, or sometimes when the limb has been subjected to surgery; neitheris it possible, with any appliance which completely encloses theextremity, for the physician to use the pin-prick test for nerveresponse at the involved extremity, nor can he carry out the essentialtests to assess the state of circulation at the extremity.

A further disadvantage of known appliances is that they are not suitedto continuous use by the patient.

These disadvantages are particularly significant in relation toappliances for use on feet and legs where as is known stimulation ofblood flow is desirable when the limb cannot be used for walking.

We have discovered a venous pump mechanism in the sole of the humanfoot, which under normal walking conditions for the foot, serves toreturn blood from the leg into the abdomen with no assistance frommuscular action.

BRIEF STATEMENT OF THE INVENTION

According to one aspect of this invention, there is provided a medicalappliance comprising an active device for engagement, in use, with atleast the sole of a human foot, said device being operative, in use ofthe appliance, to apply pressure cyclically to said sole thereby tostimulate the venous pump mechanism in said foot.

Essentially, said active device includes means to render said deviceactive when said foot is not in use for ambulation.

According to another aspect of this invention there is provided amedical appliance comprising an active device in the form of aninflatable bag shaped for engagement with at least the sole of a humanfoot; inflation means connected to the bag and capable of inflating thebag rapidly; means to deflate the bag; and means to secure the bag to ahuman foot such that when being inflated the bag applies pumpingpressure to the sole of the foot.

DETAILED DESCRIPTION

Several medical appliances embodying this invention will now bedescribed by way of example with reference to the drawings, in which:

FIG. 1 is a view of a first appliance, partly broken away and inposition on a human foot;

FIG. 2 is a view similar to FIG. 1, but showing a sectional view of asecond appliance;

FIG. 3 is a sectional view on the line III--III in FIG. 2;

FIG. 4 is a partly broken-away plan view of the bag 1 as an article ofmanufacture, with a phantom superposed plan view of a right foot,positioned for wrapped application of the bag thereto;

FIGS. 5 and 6 are views similar to FIG. 4, to show modifications;

FIG. 7 is a side view in elevation of a slipper applied over a foot thathas been fitted with one of the inflatable foot-pump bags of theinvention;

FIG. 8 is a plan view of the slipper of FIG. 7, in flattened condition,prior to use; and

FIG. 9 is a simple graph of pressure as a function of time, in aid ofdiscussion of use of the invention.

Referring to FIG. 1, the appliance here shown comprises an inflatablebag 1 formed of plastics material and shaped for engagement with thesole 10 of a human foot 11 in the plantar arch thereof. The bag 1 isconnected by way of a flexible pipe 2 to a pump apparatus 3 by which thebag 1 can be inflated.

The bag 1 may be secured to the foot 11 by a suitable slipper or byadhesive means, but in the form shown a cloth sling 4 embraces the bag 1and is secured over the instep 12 of the foot 11. Padding material canbe located between the sling 4 and the instep 12 if necessary ordesirable, and it is generally recommended that a porous knitted orother fabric such as stockinette be first applied to the foot so as tobe interposed between the bag 1 and the foot, thus allowing forventilation and preventing chafing of the skin.

The sling 4 and bag 1 are covered by a cloth slipper 6 which covers themajority of the foot 11.

In use of the appliance when secured to a foot as shown in FIG. 1, thepump apparatus 3 operates rapidly to inflate the bag 1 which whenapplies a pumping pressure to the sole 10 of the foot 11, and also urgesthe ball and heel of the foot away from each other, thus flattening theplantar arch as would occur if the foot 11 were placed on the groundduring normal ambulation, thereby stimulating venous blood-flow.Preferably, an accumulator tank is part of the pump apparatus 3, thesame being continuously charged by the pump, and having the capacity forrapid inflation of bag 1. A valve arrangement (not shown) in the pumpapparatus 3 then allows the bag 1 to deflate, whereafter the bag 1 isagain inflated, the inflation/deflation cycle being repeated as long astreatment with the appliance is required.

Preferably inflation of the bag 1 is effected in two seconds or less toprovide a satisfactory pumping action, while deflation of the bag 1 cantake as long as is necessary for the return of blood to the veins of thefoot 11.

The treatment thus provided simulates walking on the foot 11, andthereby improves venous blood circulation in a person being treated whowould normally be unable to walk or possibly even stand on the foot.

As a modification of the above described appliance, the valvearrangement in pump apparatus 3 can be dispensed with, the pumpapparatus serving only for cyclic inflation of the bag 1, and at leastthe surface of the bag 1 in contact with the foot 11 being formed withair leakage orifices thereby to be permeable to air, or being made of amicroporous material which is inherently permeable to air. Such asurface can be provided as will give the required period for deflationof the bag 1.

Such an appliance gives the advantages that the air leaving thepermeable surface of the bag 1 serves to prevent accumulation ofmoisture between the bag 1 and the foot 11, thus enhancing the comfortof the user of the appliance and making skin problems less likely.

A particular advantage of the appliance of this invention is that it canbe used when a foot is to be encased in a plaster cast, or when the legcarrying the foot 11 has been subjected to surgery.

FIGS. 2 and 3 of the drawings show an appliance in position for use on ahuman foot 11 under a plaster cast 100, the same reference numerals asused in FIG. 1 being used for corresponding parts.

The appliance shown in FIGS. 2 and 3 is similar to that shown in FIG. 1,but is larger and extends not only under the sole 10 of the foot 11, butalso around the inside of the foot 11 and over the instep 12 of the foot11.

For use, the appliance is positioned on the foot 11 and the plaster cast100 is then formed over the bag 1 as required, with the pipe 2 from thepump apparatus 3 passing either through a hole in the cast 100 or out ofone end of the cast 100.

The bag 1 can be maintained in a partially inflated condition while theplaster cast 100 is formed, whereby allowance for subsequent possibleswelling of the foot 11 is made.

More specifically, and referring to FIG. 4, the inflatable bag 1 maycomprise two like panels 20-21 of flexible material, such as PVC orpolyurethane film, peripherally sealed to each other as indicated at anedge seam 22. Each of the panels comprises a plantar-aspect sole area Aconfigurated to longitudinally lap essentially only the region of thefoot between adjacent plantar limits of the ball and heel of the footand to extend into substantial register with lateral limits of the soleof the foot. The panels 20-21 also include, within the same peripheralseal or seam 22, an integrally formed dorsi-medial area B which extendstransversely from one edge of the sole area A to a transverse extentwhich is substantially as great as the longitudinal extend of the areaA. Typically, as shown, for a foot requiring a shoe in the size range 9to 12, the longitudinal extent X of the bag is about 7 inches, and themaximum transverse extent Y of the bag is about 8 inches. The averagewidth W_(X) of the sole area A is about 2.75 inches, and the reducedwidth W_(Y) of the area B is about 2 inches. Along its anterior edge C,the area B is substantially straight and transverse to the longitudinaldirection of area A, and along its posterior edge D, the area B tapersin a concave sweep from the heel end of area A to the narrow transverseend at width W_(Y), the inlet pipe 2 having sealed entry approximatelymidway along the edge D.

What has been described for bag 1 in connection with FIG. 4 will in andof itself serve well as an article of manufacture, in the gauze, muslin,bandage material and/or adhesive tape may be relied upon to retain acircumferentially wrapped application of the bag to the foot. However,to facilitate such application without initial resort to such otherinstrumentalities, FIG. 4 additionally illustrates present preferencefor a flexible anchor tab 23 (as of vinyl sheet) which is integrallyformed with bag 1, extending laterally beyond seam 22 at thelongitudinal edge E of area A, and for a tie-down tab 24, alsointegrally formed with bag 1 beyond seam 22 at the transverse tip F ofarea B. A peel-off strip 25 of suitable release material is shownprotecting a coating of pressure-sensitive adhesive on tab 24, so thatupon adhesive exposure, tab 24 may be "tacked" to tab 23 in adjustablysecured retention of the wrapped application of bag 1 to a foot. And itwill be noted for the preferred relatively non-stretch nature of thematerial of tabs 23-24, a "tacked" circumferential completion of thewrap, involving a fastening of tab 24 in outer-end lap with tap 23, willenable circumferential hoop-tension force to be relatively uniformlydistributed along substantially the entire longitudinal extent of areaA, i.e., along edge E, thus assisting in the plantar-arch flatteningaction described above. Plural apertures in the larger tab 23 allowventilation of adjacent skin but do not impair the indicateddistribution of hoop-tension force.

Although FIG. 4 happens to show bag 1 for the situation in which theright foot is accommodated, it will be understood that the sameaccommodation to the left foot may also be made by the same article ofmanufacture. In application to the left foot, the plan view of FIG. 4 isreversed, from left to right, by placing the panel 20 on the bottom,beneath panel 21, and the pressure-sensitive adhesive is just as"tackable" to tab 23 as before, except for being engaged beneath tab 23.

As has already been noted, the release of pressure fluid after eachpulsed delivery of inflation pressure is suitably via pores or aperturesin one or both of panels 20-21. It may be found convenient tomanufacture the bag 1 without such pores or apertures, using puncturablematerial. And the surgeon who makes the fitted application to apatient's foot need only first blow the bag via his mouth, then holdinlet 2 closed with a finger, while he uses a needle or other sharplypointed instrument to make plural punctures of the panel (20 or 21)which is to be adjacent the sole of the patient's foot; such puncturingmay proceed while the surgeon squeezes the bag to satisfy himself thatthe desired degree of fluid leakage will be achieved in use. On theother hand, we prefer that bags 1 be marketed with existing perforationsin each of two configurations, one specifically committed to right-footapplication and the other specifically committed to left-footapplication.

The described bag 1 of FIG. 4 will be seen, in cyclically pressurizeduse within the circumferential bandage or sling 4 of FIG. 1, or withinthe cast 100 of FIGS. 2 and 3, to provide a peripherally continuousconfinement of the midtarsal and plantar regions of a foot, with theaction of rapidly shrinking the confinement in a cylindrical pattern ofrelatively rapid short-duration release from shrink action. Morespecifically, this confinement and cyclical action may be viewed as themeans of providing (a) upward and spreading force at longitudinallyspaced plantar regions of the sole of the foot, said regions beingessentially limited by and between the ball and heel of the foot and (b)downward force at the region of the midtarsal joint. As a result of theindicated cyclical pattern, the arch is caused to flatten periodicallyand thus to stretch and neck down the internal sectional area of theveins of the lateral plantar complex, with resulting venous-pump action.Viewed in a still further light, this confinement and cyclical actionwill be seen as the means of providing vertically opposed squeezingforces between the plantar region of the sole of the foot and the regionof the midtarsal joint, to thereby stimulate the venous-pump mechanismof the foot.

In all cases, it is important and deemed significant that neither thedistal calf pump nor the proximal calf pump, nor any other of thesignificant pumps of the venous-return system of the involved leg isactuated in time-coincidence with foot-pump actuation. This factillustratively enables the described invention to be operative within acast, or to be operative in a region remote from orthopedic fixation ofa damaged tibia, knee, or femur, or to be similarly remote from theregion of a vein-transplant operation and thus to relatively rapidlydissipate the pain and swelling which are the normally expectedpost-operative consequence of such an operation. In spite of theremoteness of foot-pump actuation from these other regions of trauma,the fact of no other pump involvements means that foot-pump drivenvenous return flow can be substantially unimpeded in its direct deliveryto and through the region of trauma.

FIGS. 5 and 6 are further inflatable-bag embodiments of the invention,although they are presently of lesser preference, as compared to theembodiment of FIG. 4.

In FIG. 5, an inflatable bag 30 is longitudinally elongate andcorresponds generally to the function and placement of area A of the bag1 in FIG. 4. Bag 30 thus is designed for application to the plantarregion of the sole of the foot, being cyclically inflatable via aflexible inlet pipe 31 sealed to bag 30 via locally sealed accessthrough the peripheral seam 32 of the bag. A perforated flexible tab 33corresponds to the tab 23 of FIG. 4, and a similar but ultimately morenarrow and more extensive tab 34 is connected to the oppositelongitudinal edge of bag 30, being adhesively coated and protected bypeel-off material 35. A retaining hoop is circumferentially completed bypressure adhesion of tab 34 to tab 33. In a cyclical application ofpressure fluid to the device of FIG. 5, it is the longitudinalflattening of the arch which is primarily responsible for foot-pumpstimulation.

In the arrangement of FIG. 6, an inflatable bag 40, served by an inletpipe 41 and peripherally sealed at seam 42 is generally rectangular butelongate in the direction transverse to the longitudinal direction ofthe foot (phantom outline); and end tabs 43-44 correspond to thosepreviously described, to enable pressure-adhered completion of acircumferential hoop or belt around the midtarsal/plantar regions of thefoot. In a cyclical application of pressure fluid to the device of FIG.6, it is the generally vertical squeezing action at themidtarsal/plantar region which is primarily responsible for foot-pumpstimulation, i.e., virtually without any arch-flattening action.

In certain post-operative situations wherein a part of the leg otherthan the foot is involved, it is therapeutically beneficial not only tooperate the foot pump but also to allow the patient a degree of freedomto stand and walk on his installed foot-pump bag 1, or 30, or 40. Insuch a situation, a fitted slipper 50 is most useful, and may take anyone of a variety of forms, so that FIGS. 7 and 8 will be understood tobe merely illustrative of one of these forms.

The slipper 50 comprises a sole member 51 of relatively rigid, porous,light-weight material, centrally adhered to a sheet 52 of light-weightduck or canvas, leaving flexible lateral flaps M-N projecting laterallybeyond the respective longitudinal side edges of sole member 51; flapsM-N are adapted for wrap-around fit to the particular foot, the lap offlap M over flap N being visible in FIG. 7. Woven-fabric straps53-54-55-56 have centrally-sewn connection to the underside of sheet 52,at regions marked 53'-54'-55'-56' in FIG. 8, leaving free ends forcompletion of circumferential fastening of sole member 52 to the foot ateach of three longitudinally spaced locations; it is convenient to haveone end of each strap fitted with a wire bail, so that the other end ofeach strap can be threaded through the corresponding bail and beVelcro-fastened against itself, to hold each adjusted strap connection.

A tail portion 52' of fabric sheet 52 extends rearward of a smallyieldable heel step 57 at the back end of sole member 51, and tailportion 56 is characterized by like, oppositely directed tabs 58-59,each of which has an exposed patch of Velcro loop material 58'-59'.These patches are selectively engageable with patches 60-61 of Velcrohook material sewn to the underside of panels M-N, as viewed in thesense of FIG. 8. A thin panel 62 of anti-skid material is bonded to theunderside of the described assembly, to complete the slipper.

In use, and after installation of an inflatable-bag (1,30, 40) with itsinlet pipe illustratively projecting upward and rearward from the innerlateral side of the ankle, the flaps M-N are first folded into overlapover the midtarsal region, and the straps 53-54-55 set to hold theoverlap. Then, tail 56 is folded upward and each of the tabs 58-59 iswrapped around the back of the heel, into completion of Velcroengagements, at 58'-60 and at 59'-61, respectively. The slipper andfoot-pump actuator are now in readiness to accept cyclicalpressure-fluid stimulation via connection to inlet 2. It will beunderstood that the relatively rigid sole member 51 provides anexcellent reference against which to react, upon bag inflation, forapplication of arch-flattening and/or midtarsal/plantar squeezing actionof the nature discussed above.

As a modification of the appliances thus far shown and described, itwill be understood that inflatable foot-pump bag 1 can be incorporatedin an article of footwear, such as a conventional boot, to be worn by aperson needing to use the appliance.

An inflatable bag 1 of the nature described in connection with FIG. 4never requires a large volume change in proceeding through itsinflation/deflation cycle. The maximum inflated volume is in the orderof 300 to 350 cc, and on deflation the inflated volume can be expectedto reduce to 100 to 120 cc. Thus, the pressure-fluid supply equipment 3may be relatively small and convenient for table-top or shelf mounting,with flexible-hose and disconnectable coupling to the inlet pipe 2; thisis true, whether the supply and control means 3 is merely timed valvingto assure programmed delivery of pressure pulses of a fluid, such asoxygen from a locally available tank supply, or the means 3 incorporatesits own pumping and/or accumulator mechanism to provide the neededpressure fluid. Whatever the alternative, standard regulator, bleedorifices, time delay devices and their adjustability are all well knownand therefore the supply means 3 may take on a variety of differentphysical embodiments. What is important, however, is that delivery ofpressure fluid to inlet 2 and the bleed of fluid through pores and/orapertures and/or valving in the deflation phase shall meet certaincriteria. Presently preferred criteria will be stated in the context ofFIG. 9, which shows pressure P to develop quickly in the inflation phasea and to dissipate somewhat exponentially, in the deflation phase b.

Although it has been stated above that bag 1 should be inflated in twoseconds or less, it is perhaps more accurate to state that in ourexperience to date the inflation should be as quick as possible, toimitate the normal impact of the sole of the foot on the ground whenwalking. Such fast inflation imparts a jerk or sharply pulsed action inreturn blood flow, and such action is likely to be helpful in preventingvenous thrombosis. It is believed that maximum velocity, howevertransient upon pulsed excitation, is more important than total bloodflow. The veins have check-valve formations, and the downstream side ofeach check valve is a site where stagnation and clotting may occur; itis believed that with bag inflation as rapid as possible, the openingphase for each check valve is correspondingly rapid, thus locallystirring stagnant return-flow blood and reducing the chances of aclotting constriction of return-flow passages.

The peak pressure P for any delivered inflation impulse should be thatwhich is sufficient to produce the appropriate venous impulse, whilstnot being too uncomfortable for the patient to tolerate. This will ofcourse mean a different peak pressure P which will be various, dependingupon the particular patient and his affliction. However, it can be saidthat, in our experience to date, a peak pressure within bag 1 (20, 30,or 40) of 200 to 220-mm Hg has been satisfactory, although there may betimes when it is advisable to use a peak pressure somewhat greater than220-mm Hg. Such peak pressure has produced comfortable actuation of thepatient's foot pump, in the circumstance wherein the supply apparatus 3has provided time-switched delivery of oxygen from a pressurized tankand wherein the inflation time a was 0.4 second.

The total period (a+b) of the inflation/deflation cycle will also bevarious, depending upon the confronting pathological condition and, inparticular, on the severity of venous obstruction and on how quickly thephysiological venous pump becomes filled. As a rough guide, it can besaid that in severe venous obstruction, as in a limb with markedswelling, the period of the cycle might be as frequent as every 10seconds. In moderate swelling, 30 seconds would probably be adequate,whereas for maintenance purposes a 60-second cycle should suffice. Theoptimum frequency of the cycle can be audibly determined by theclinician, listening to the flow in the posterior tibial veins with aDoppler monitor.

Although the interval between inflation pulses is very much greater thanthe indicated rapid inflation time a, deflation should commenceautomatically at achievement of predetermined peak pressure, and initialdeflation should be rapid and follow an exponential pattern. Thus, wecurrently recommend leakage in bag 1 to the extent that, for example,for a peak pressure P of 210-mm Hg, deflation to 30-mm Hg should be inabout one second, and to 20-mm Hg in about 1.9 seconds. A timer, withinapparatus 3, reinitiates the cycle upon predetermined time-out of theinterval b.

Operations in which the described foot-pump actuating means are likelyto be particularly useful include leg fractures and operations aroundthe knee joint, where the leg veins may become compressed either duringor after an operation. It has been found very useful in arterial andvein-graft operations, where some of the leg veins have had to beligated and where the collateral venous-return channel (the longsaphenous vein) has had to be removed for use as an arterial graft.

It will be seen that the described uses of the invention involve amethod of promoting venous pump action in the leg of a living body andthat, from one aspect, steps of the method comprise (a) application of acircumferential tie to the foot at the region of the midtarsal joint,(b) applying upward and spreading force between the circumferential tieand the foot at longitudinally spaced plantar regions of the sole of thefoot, said plantar regions being essentially limited by and between theball and heel of the foot, (c) relaxing said force for a period of time,and (d) cyclically repeating the force-application and force-relaxingsteps in a pattern wherein force application is relatively rapid,whereby the arch of the foot is periodically caused to flatten and thusto stretch the neck down the internal sectional area of veins of thelateral plantar complex, with resulting venous-pump action.

From another aspect, steps (a) and (b) of the above method are modifiedto the extent that the upward and spreading force is in reaction todownward force at the region of the midtarsal joint, i.e., verticallyopposed squeezing forces between the region of the midtarsal joint andthe plantar region therebeneath. From a still further aspect, steps (a)and (b) may be viewed as establishing a peripherally continuousconfinement of the midtarsal and vertically opposed plantar regions ofthe foot, and developing the squeezing forces through a periodicshrinking of the confinement.

What is claimed is:
 1. The method of promoting venous pump action in theleg of a living body, which method comprises simultaneously applying (a)upward and spreading force at longitudinally spaced plantar regions ofthe sole of the foot, said regions being essentially limited by andbetween the ball and heel of the foot and (b) downward force at theregion of the midtarsal joint, said forces being applied in a cyclicalpattern of relatively rapid increase to a predetermined upper limitbefore relaxation for a period substantially exceeding the applicationtime, whereby the arch of the foot is caused to flatten periodically andthus to stretch and neck down the internal local sectional area of theveins of the lateral plantar complex, with resulting venous-pump action.2. The method of promoting venous pump action in the leg of a livingbody, which method comprises simultaneously applying vertically opposedsqueezing forces between the plantar region of the sole of the foot andthe region of the midtarsal joint, said forces being applied in acyclical pattern of relatively rapid increase to a predetermined upperlimit before relaxation for a period substantially exceeding theapplication time, thereby to stimulate the venous pump mechanism of thefoot.
 3. The method of promoting venous pump action in the leg of aliving body, which method comprises establishing a peripherallycontinuous confinement of the midtarsal and plantar regions of a foot,and shrinking the confinement in a cyclical pattern of relatively rapidshort-duration shrink action followed by a relatively long-durationrelease from shrink action.
 4. The method of promoting venous pumpaction in the leg of a human body, which method comprises the steps of(a) applying a circumferential tie to the foot at the region of themidtarsal joint, (b) applying upward and spreading force between thecircumferential tie and the foot at longitudinally spaced plantarregions of the sole of the foot, said plantar regions being essentiallylimited by and between the ball and heel of the foot, (c) relaxing saidforce for a period of time, and (d) cyclically repeating theforce-application and the force-relaxation steps in a pattern whereinforce-application is relatively rapid, whereby the arch of the foot isperiodically caused to flatten and thus to stretch and neck down theinternal sectional area of veins of the plantar complex, with resultingvenous-pump action.
 5. The method of claim 4, in which thecircumferential tie is established by wrapped application of a clothsling.
 6. The method of claim 4, in which the circumferential tie isestablished by application of an orthopedic cast.
 7. The method of claim4, in which the circumferential tie is short of enveloping the toes ofthe foot.
 8. The method of claim 4, in which the force application isdeveloped in two seconds or less.
 9. The method of claim 4, in which thecircumferential tie is established by securing a slipper to the foot.10. The method of claim 4, in which said force is pneumatically applied.11. The method of promoting venous pump action in the leg of a livingbody, which method comprises the steps of (a) applying verticallyopposed squeezing forces to the foot at the region of the midtarsaljoint and at the plantar region therebeneath, (b) relaxing said forcesfor a period of time, and (c) cyclically repeating the force-applicationand the force-relaxation steps in a pattern wherein force-application isrelatively rapid, whereby the veins of the plantar complex areperiodically compressed, with resulting venous-pump action.
 12. Themethod of promoting venous pump action in the leg of a human body, whichmethod comprises the steps of (a) establishing a peripherally continuousplantar confinement of the foot at the region of the midtarsal joint,(b) shrinking the confinement, (c) relaxing the shrinking confinement,and (c) cyclically repeating the shrinkage and relaxing steps in apattern wherein the shrinkage step is relatively rapid, whereby theveins of the plantar complex are periodically compressed, with resultingvenous-pump action.
 13. The method of promoting venous pump action inthe leg of a human body, which comprises the steps of (a) selecting arelatively stiff sole member of length to overly the ball and heel ofthe foot and to span the plantar arch, (b) securing the same to the footwith referencing support at the ball and heel, (c) applying upward forcebetween the sole member and the plantar arch, (d) relaxing said forcefor a period of time, and (e) cyclically repeating the force-applicationand the force-relaxation steps in a pattern wherein force-application isrelatively rapid, whereby the internal sectional area of the veins ofthe plantar complex is periodically reduced, with resulting venous pumpaction.
 14. The method of claim 5 or claim 11 or claim 12 or claim 13,in which the force application is developed in one second or less. 15.The method of claim 5 or claim 11 or claim 12 or claim 13, in which theperiod of force-relaxation is in the range of 10 to 60 seconds.
 16. Themethod of claim 5 or claim 11 or claim 12 or claim 13, in which theforce-application step is pneumatic and to a peak pressure of at least200-mm Hg.